1. Field of the Invention
The present invention relates to a film feeding apparatus of a camera and more particularly to the construction of the mechanism for stopping the feeding of the film each time one frame of the film is fed.
The present invention also relates to a film feeding apparatus of a camera having an automatic initial loading function for feeding out the film from a cartridge after the cartridge is installed in a cartridge chamber of the camera and winding the film round a spool provided in the camera.
2. Description of the Related Arts
Normally, the film feeding apparatus of a camera automatically stops the operation for feeding the film each time the film is fed by one frame, by utilizing perforations formed in the film. In a camera using an ordinary 35 mm film having perforations formed therein at small regular intervals, the film feeding is stopped when the rotational angle of a sprocket engaging perforations reaches a predetermined value. For example, a camera for use with 110 type film having one perforation formed in each frame at regular intervals has a mechanism comprising a perforation detecting lever having a claw which penetrates into each perforation and a spring for urging the lever in the direction in which the claw presses against the film surface. In this mechanism, the claw penetrates into one perforation and engages with it while the film is being fed. Thus, the film is prevented from moving. In using the film having one perforation formed for each frame, the mechanism for stopping the feeding of the film by means of the lever can be constructed comparatively easily.
In the meantime, the present applicant proposed a camera which uses a film having two perforations formed in one frame in Japanese Patent Application 2-092579. If the lever mechanism of the camera for use with 110 type film is applied in the camera using film having two perforations formed for one frame, it is difficult to distinguish whether the claw of the lever has penetrated into the front perforation or the rear perforation in each frame, which causes the control system and the construction of the camera to be complicated.
In using film having two perforations formed for one frame, it is considered that the claw of the lever is allowed to penetrate into only the front perforation. More specifically, the lever is interlocked with a shutter charging mechanism so as to move the lever away from the film surface when the rear perforation passes the position corresponding to the claw of the lever. However, a mechanism in which the operation timing of the lever is controlled by interlocking the lever mechanism with a different mechanism leads to a limitation in designing or assembling the camera. In addition, if the lever is operated at an inappropriate time, the control for winding the film cannot be appropriately accomplished. These problems may occur when one frame has more than two perforations.
The following initial loading function is known. That is, a film is automatically fed out from a film cartridge after a user installs it in a cartridge chamber of a camera and the film is automatically wound round a spool of the camera. In this initial loading mechanism, when the film fed out from the cartridge advances toward the spool, the film is prevented from proceeding if there is an obstacle on the film feeding path. In the mechanism of the camera for use with 110 type film, the lever described above is urged so that the claw presses against the film surface. That is, if the lever mechanism of the camera for use 110 type film is employed in a camera having the initial loading mechanism, the claw of the lever prevents the feeding of the film during the initial loading operation.
In order to adopt a mechanism equivalent to the lever mechanism of the camera for use 110 type film in the camera having the initial loading mechanism, it is necessary in initial loading to move the claw of the perforation detecting lever away from the film feeding path by interlocking the operation of the perforation detecting lever with that of the film feeding mechanism or by a user's manual operation. However, in the former, the construction of the film feeding apparatus and the control system thereof because complicated. In the latter, it is necessary for the user to perform an operation, which may lead to an operation mistake.